Integration of mass spectrometry in analytical biotechnology.

Mass spectrometry (MS) has become an indispensable tool for peptide and protein structure analysis because of three unique capabilities that enable it to be used to solve structural problems not easily handled by conventional techniques. First, MS is able to provide accurate molecular weight information on low-picomole amounts of peptides and proteins independent of covalent modifications that may be present. Second, this information is obtainable for peptides present in complex mixtures such as those that result from a proteolytic digest of a protein. Third, by using tandem MS, partial to complete sequence information may be obtained for peptides containing up to 25 amino acid residues, even if the peptides are present in mixtures. Sensitivity and speed of the MS-based approaches now equal (and in some cases exceed) that of Edman-based sequence analysis. In this perspective we discuss how MS, tandem high-performance MS, and on-line liquid chromatography/MS using fast atom bombardment or electrospray ionization have been integrated with more conventional techniques in order to increase the accuracy and speed of peptide and protein structure characterization. The expanding role of matrix-assisted laser desorption MS in protein analysis is also described. The unique niche that MS occupies for locating and structurally characterizing posttranslational modifications of proteins is emphasized. Examples chosen from the authors' laboratory illustrate how MS is used to sequence blocked proteins, define N- and C-terminal sequence heterogeneity, locate and correct errors in DNA- and cDNA-deduced protein sequences, identify sites of deamidation, isoaspartyl formation, phosphorylation, oxidation, disulfide bond formation, and glycosylation, and define the structural class of carbohydrate at specific attachment sites in glycoproteins.     

Eosinophil infiltration in nonallergic chronic hyperplastic sinusitis with nasal polyposis (CHS/NP) is associated with endothelial VCAM-1 upregulation and expression of TNF-alpha

New Zealand White rabbits (6 males and 6 females) were fed a diet of high lipid peroxide content (peroxide value: 249.05 meq/kg fat) for 21 days. Twelve rabbits served as controls (peroxide value: 40.3 meq/kg fat). The lipid peroxide loading did not cause clinical signs. The rate of lipid peroxidation, as measured on the basis of thiobarbituric acid reactive substances (TBARS), was significantly (P < 0.05) higher in all of the investigated tissues, in the following order: liver > red blood cells (RBC) > blood plasma. Reduced and oxidised glutathione content was higher in the blood plasma (P < 0.01) and liver (P < 0.001) of rabbits exposed to the peroxide load. Lipid peroxide loading decreased the activity of glutathione peroxidase in the blood plasma, RBC haemolysate and liver and that of glutathione reductase in the liver. The amount of cytochrome P450 (both CO- and metyrapone-reduced) and the activity of cytochrome c (P450) oxidoreductase in the microsomal fraction of the liver homogenate were also lower in the group exposed to lipid peroxide load. Subchronic alimentary lipid peroxide loading in the presence of sufficiently high levels of antioxidants in the complete feed was found to increase the rate of lipid peroxidation and markedly lower the activities of both the glutathione and xenobiotic transforming enzyme systems without causing any clinical signs of toxicity.     

Origin of Strength Increase of Abraded or Indented Glass upon Annealing

The mechanical strength of soda-lime and boresilicate glass rods with an extended crack was found to increase upon annealing. Since the residual stress near the extended crack tip is small, this strength increase indicates that crack tip blunting is taking place.     

High-reflectivity Bragg mirrors for optoelectronic applications

We report novel Bragg-reflecting structures that represent a departure from the conventional quarter-wavelength stacks used currently in the optoelectronics industry. These structures can be used to design high-reflectivity mirrors in strained material systems and mirrors that will provide high reflectivities in more than one wavelength band. Such mirrors can be used to design resonant-cavities for optical absorption as well as emission. Resonant-cavity photodetectors were demonstrated     

Diagnosis of carotid artery stenosis: comparison of oculoplethysmography and Doppler supraorbital examination

Both Doppler supraorbital examination (OSM) and oculoplethysmography (OPG) were administered to 101 patients (202 arteries) to document the presence or absence of hemodynamically significant lesions of the internal carotid artery prior to angiography. There was no significant difference between the OSM and OPG with respect to diagnostic sensitivity or specificity, incidence of false-negative or false-positive results, and overall diagnostic accuracy. The diagnostic accuracy for the OSM and the OPG were 94.2% and 91.6%, respectively. In 171/202 (84.6%) arteries, the OSM and OPG were in diagnostic agreement, and the overall diagnostic accuracy of the combined tests was 97%. However, when the OSM and OPG did not agree (31/202 arteries, 15.4%), the diagnostic accuracy of neither the OSM nor the OPG was acceptable. Although the best diagnostic accuracy was obtained using two means of noninvasive cerebrovascular testing, in those instances where only one test may be available, the OPG would appear to be the test of choice. In those laboratories in which high diagnostic accuracy is obtained with the OSM, the addition of OPG testing will increase the overall diagnostic accuracy to a very high level. The presence of a midcervical bruit was found to have a very poor correlation with the incidence of hemodynamically significant stenoses of the internal carotid artery. Although both the OSM and OPG have minimal value in patients with symptomatic cerebrovascular disease, these tests play a very important role in screening patients for asymptomatic carotid stenosis or atypical cerebrovascular symptoms.     

Trends in secondary organic aerosol at a remote site in Michigan's upper peninsula

The trends in secondary organic aerosol at a remote location are studied using atmospheric fine particulate matter samples collected at Seney National Wildlife Refuge (NWR) in northern Michigan. Detailed analysis of particle-phase organic compounds revealed very low concentrations of primary anthropogenic emissions and relatively high levels of organic di-, tri-, and tetracarboxylic acids thought to be indicators of secondary organic aerosols. Seasonal changes in these organic compounds were tracked by analyzing composites of monthly average samples. The concentration of aromatic and aliphatic dicarboxylic acids peak in July and taper off in the fall, which coincides with fine particle organic carbon concentration. In contrast, a chemical mass balance model used to quantify primary sources of particulate matter shows higher contributions from primary emissions in the winter. Complementing the monthly average concentrations, event-based composites of high volume samples were used to track the different species of secondary organic aerosol at the Seney NWR location. The distribution of aliphatic diacids and the aromatic di- and triacids varied with different atmospheric conditions, which suggests different precursor gases for these secondary organic aerosol components. The aliphatic diacid concentrations track with ambient concentrations of particle-phase pinonic acid. In addition, back-trajectories for the eight event-based composites are compared to the organic acid distributions and are linked to the distribution of organic acids present in the composites.     

Genetic variation of pancreatic esterase isozyme in Japanese quail

A genetic variation was found in pancreatic esterases of Japanese quail which appeared to be arylesterase. It was found on the cathode side in the agar gel electrophoresis. Three phenotypes, A,B and AB, were observed. These phenotypes were shown to be controlled by one autosomal locus, designated as Es-4, with co-dominant alleles Es-4A and Es-4B. Es-4 esterase isozymes were detected in all the individuals from about 4 days of age, but the activity was very weak. However, it gradually increased to reach a level almost the same as that of a mature quail from about 15 days of age.     

Field Survey of Permeable Pavement Surface Infiltration Rates

The surface infiltration rates of 40 permeable pavement sites were tested in North Carolina, Maryland, Virginia, and Delaware. Two surface infiltration tests (pre- and postmaintenance) were performed on 15 concrete grid paver lots filled with sand. Maintenance was simulated by removing the top layer of residual material (13–19?mm). Simulated maintenance significantly (p<0.007) improved the surface infiltration rate. The median site surface infiltration rate increased from 4.9?cm/h for existing conditions to 8.6?cm/h after simulated maintenance. Fourteen permeable interlocking concrete pavers (PICP) and eleven porous concrete (PC) sites were also tested. PICP and PC sites built in close proximity to disturbed soil areas had surface infiltration rates significantly (p<0.0014 and p<0.0074, respectively) less than stable landscape sites. Median PICP surface infiltration rates of each condition were 80?cm/h and 2,000?cm/h, respectively. Median PC surface infiltration rates with and without fines were 13?cm/h and 4,000?cm/h, respectively. This study showed that: (1) the location of permeable pavements; and (2) maintenance of permeable pavements were critical to maintaining high surface infiltration rates.